Catalyst
by Captain Zangano
Summary: Light maliciously slows down L's metabolism.
1. Chapter 1

**Disclaimer:** I don't own Death Note, or make any money from this fanfic

**A/N:** This is a prompt fic from the Death Note Kink meme on Livejournal. The prompt was: "Light maliciously slows down L's metabolism, at first to lower his confidence and make him lose, but then Light ends up liking it."

**Pairing: ** L/Light, though it's not very romantic.

**Rated M** for non-explicit sexual content

* * *

After only one month at To-oh University, Light was already pretty famous on campus. And not just for getting a perfect score in all subjects on the entrance exam, or for the epic tennis match with Ryuga. No, Light had managed to become an unofficial research project consultant for grad students. No project was without problems, and sometimes when hitting a roadblock, or encountering a minor setback, it was useful to get a second opinion. They would bring him the relevant literature, buy him a cup of coffee or tea, and wait for the genius to provide some much needed insight. He would read over the articles, make notes, ask questions and give his opinion. And he was so polite and helpful that they would often buy him gifts to thank him for his time.

Best of all, this was an area where Light could easily beat L, thanks to his social intelligence. Two weeks ago a hapless grad student had decided to try asking the other student who had received a perfect score on the entrance exam for advice. Bad idea. After five minutes, Yoshiaki was dryly informed that if he was having trouble isolating the chemicals in recruitment pheromones for _Vespa mandarinia japonica,_ perhaps he should re-take introductory organic chemistry. Word spread, and L hadn't been consulted again. Light smirked inwardly at the thought. For all his intelligence L had very little tact. A fact which made it all the more satisfying to excel in an area where L had failed. True, his time could be better spent judging criminals, but Kira was a benevolent god, occasionally deigning to impart his genius for the betterment of humanity (but only for the good people who deserved it). Additionally, when Kira officially became god of the new world it would be nice to have scientists on his side. Maybe after he had weeded out all the criminals and bad people he could start improving science by cleaning out all the incompetent scientists…

Light sipped his tea and smiled politely at the grad student across from him. Ketsu Mori, currently majoring in biochemistry. She was working on a research project studying the effects of catalytic enzymes on metabolism. And according to the scientific articles that she had given him, she was also studying artificial sweeteners. Interesting.

He frowned slightly at the thought. All this talk of metabolism reminded him of a certain sugar-addicted-detective. The amount of sugar that L consumed was positively revolting. He spent most of the day dangling one sweet or another in front of his mouth, only to slurp it up with a disgusting noise. The taskforce members sometimes took bets as to how many sugar cubes L could fit into one cup of coffee. It was amazing that the detective hadn't gotten diabetes, or had every single tooth rot and fall out of his mouth. Even worse, he never seemed to gain a single pound no matter how much he ate. Light had to exercise and eat healthy to maintain his weight. Life just wasn't fair.

Light finished reading a paper detailing the various catabolic pathways, and started on another that detailed energy use and storage. He took notes at all the relevant points, mostly for Ketsu, since he would be able to easily remember everything he read, but she might want notes later.

If most people burn energy, he imagined that L's metabolism must be a frickin inferno. Like one of those trains from an old movie. No matter how much coal is shoveled on the fire, it just keeps going faster, burning. Most people's bodies would store fat when excess energy was generated, but not L.

Light finished reading the last of the papers and started going over Ketsu's research proposal. It was an intriguing project: she wanted to synthesize a compound that would eventually help people with metabolic problems lose weight. She had started with an artificial sweetener, then added a catalytic enzyme. The idea was that someone could sweeten their food without calories, and even burn more calories by speeding up the break-down of the rest of the food they ate. There had been encouraging results in the in vitro test run, and then she had moved on to rats.

"So I tried adding the catabolic enzyme enhanced sucralose as a dietary supplement, hoping that it would stimulate the metabolism of the rats," Ketsu explained. "But it seems to have had the opposite effect."

"Really?" Light leaned forward. His interest was no longer politely feigned.

"Yeah. All the rats that received the extra compound gained twice as much weight as the control group."

"Wow that's amazing." Light's mind raced at the possibilities. If this substance had caused such a dramatic weight gain in rats, maybe it would have a similar effect on humans. Maybe… maybe it would even slow down L's monster metabolism. He wondered what the detective would do if he mysteriously started gaining weight. Perhaps if he felt he wasn't in control of his own body, his confidence would decrease. It might distract him from the case and give Light the edge he needed to outmaneuver him.

"Yeah, I guess it is kind of interesting," Ketsu continued. "It must make the body go into starvation mode and start storing as much energy as possible as fat. Which is kind of interesting since some studies on artificial sweeteners and cutting calories have hinted that might happen." She sighed. "I know my findings are probably good enough to publish, but I'm still kind of bummed that the compound didn't work like I wanted it to."

"I wonder what would happen if you tried making a molecule that temporarily bound up some of the catalytic enzymes. Maybe the body would overcompensate and use up more energy."

Ketsu brightened at the suggestion. "Hey, that's a great idea. I'll have to try that next."

"Hmm, do you think I could visit your lab sometime?"

"What? Oh sure, that'd be great!" Ketsu exclaimed. "Let me know if you need anything to pay for your time. You've been very helpful."

"I'm just glad I could be of assistance." Light bowed and smiled politely. "But if I think of anything, I'll let you know."

Three days later, Light had a 2 kilo supply of beta-sucralose. It was finely ground, and looked identical to regular table sugar, but was about ten times sweeter. Even better, it was an undocumented substance, and if any lab tested it, they'd probably think it was just regular sucralose. It was also a substance that had never been used on humans, but it was about time that L played test subject for once.

"L, the rules of the game are about to change again," Light said with a malicious smile.

**~o~**

Ironically, the hard part would getting L to eat the sweet stuff. Light knew that as a suspect, L would be suspicious if he suddenly brought in a batch of sweets, and would probably make the other task force members eat it as well. He might even turn it into a game of "If you don't eat this, your Kira percentage will rise," for his prime suspect. Light shuddered at the thought.

No, the best way to get the sweet compound to L was to utilize another task force member. But how? Then Light had an idea. It was such a brilliant idea, that he might have been surprised, if his own brilliance was ever capable of surprising him. He would use L's disgusting habits against him.

Light could practically visualize L plinking one sugar cube after another into his coffee cup, thoughtlessly sloshing the liquid around and making stains that Matsuda or Watari would have to clean up later. Light chuckled quietly. "L, do you know, being such a slob is going to be your downfall?" he whispered to himself.

**~o~**

Light arrived earlier than usual at the hotel in order to put his plan into motion. As planned, Matsuda was the only other task force member in the kitchen area, cleaning up and preparing the food. Apparently, Watari, L, and the others were off watching surveillance videos in another room.

"Hey, Matsuda, do you want help making coffee?" Light offered.

Matsuda looked up, surprised, then smiled happily. "Sure, Light." Then he looked down. "But, ah, don't you have something more important to be doing?"

Light decided a little flattery might go a long way. "Matsuda, I know the others don't always appreciate everything you do, but I just wanted to say that I do. Every job, no matter how insignificant it might seem is essential and important in its own way." Light paused in his flattery to give Matsuda a brilliant smile. "I think it admirable that you are always willing to do the less glamorous work."

Matsuda blushed. "Thanks, Light, that's very kind of you."

"If L worked all by himself, imagine what a pigsty this place would be by now."

Matsuda laughed and brightened up. "You know, you're right, Light. If no-one else wanted to get the food or clean up it'd never get done."

He arranged the cups and serving plates, then picked up the jar of coffee grounds at the most opportune moment. "Hey, Matsuda, I have an idea, why don't we just mix sugar into L's coffee grounds? Then his coffee will be sweet enough to start with, and he won't have to waste so much time mixing sugar cubes into his cup."

Matsuda thought about that for a moment. "That's great idea, Light!"

Yes, Matsuda would definitely be in favor of such an idea, especially since the detective was often stuck cleaning up the numerous coffee stains that L made throughout the day.

Then he paused in thought for another moment. "But the rest of us can't drink coffee as sweet as L likes his."

"That's okay, we can just keep his coffee separate," Light said smoothly.

Light labeled a container "pre-sweetened coffee" and started mixing the beta-sucralose into the grounds.

Matsuda stuck a finger in the sugar and tried a few grains. "Wow, that's really sweet," he exclaimed.

Light's eye twitched as he carefully suppressed his annoyance. Fortunately Matsuda hadn't ingested enough to notice a difference in weight gain - he hoped. It took about five seconds to come up with a convincing lie. "It's finely ground sugar - it tastes so sweet since it has increased surface area."

Matsuda looked impressed. "Wow, you're so smart Light! You'll probably be the smartest detective in the whole world after you graduate from college." Matsuda scratched his head. "Well maybe the second smartest after L."

Light glared at Matsuda briefly before he could stop himself.

Matsuda laughed nervously. "Or maybe you'll be smarter than L, I don't know, I have trouble telling which genius is smarter."

Light forced himself to give Matsuda a pleasant smile. "Thanks, Matsuda."

**~o~**

L poured himself a cup of coffee, then grabbed a sugar cube to plop into the liquid.

"You don't have to add any sugar, Ryuuzaki," Matsuda happily informed him. "The coffee has already been sweetened."

"Indeed," L said blandly.

"Yeah, Light helped me come up with the idea. We mixed sugar in with your coffee grounds so now you won't have to spend so much time mixing in sugar cubes."

Light mentally face palmed. He had hoped Matsuda would forget to mention him. Maybe manipulating Matsuda hadn't been that great of an idea. But there was nothing inherently suspicious about adding sugar to coffee, was there? "I thought it would be a more efficient use of your time," Light said innocently. "And now Matsuda won't have to clean up so many coffee stains."

L gave Light a suspicious stare, but carefully sipped his coffee. From the look on his face he didn't taste anything out of the ordinary. Then he gave Light a defiant glare and deliberately added one sugar cube. "It's not quite as sweet as I like it," he informed them. He sloshed the coffee around on purpose as he stirred in the sugar. L was such a brat sometimes.

**~o~**

Light carefully closed and locked his bedroom door behind him before allowing himself a victorious smirk. It had only been two weeks since he supplemented L's coffee, and already he was beginning to see results. They weren't very obvious results, and no-one else had probably noticed, but Light's trained eyes had picked up on the fact that L's baggy jeans didn't sag as much as they used to, and the detective's cheeks were starting to fill in and puff out.

He was still having a hard time keeping ahead of L with the second Kira/Misa fiasco, but he'd eventually win that one as well.

Light smirked again and imagined L gaining more and more weight. Would he wonder what was happening? Would he figure it out?

Light had outsmarted him, and without even using the death note. L was in his power and he didn't even realize it yet. He considered using the death note to send another message: "L you seem to be gaining weight," or "L, do you know, sugar is bad for your health," or perhaps he could have Hideki Ryuga make 23 days of pop songs about overweight detectives. It was almost worth the risk of getting caught.

Yes, the death note was merely a tool, Light was the smarter genius here.

Light glanced up at the Shinigami who was staring at him, being entertained. "Ryuk, you're really lucky I'm the one who picked up your death note."

Ryuk laughed. "Yeah, I'm sure no-one else would be as modest as you are."

Light gave Ryuk a quick glare, then went back to plotting world domination.

He should probably be using this time to judge criminals, but gloating was just so much fun. Light flopped onto his bed and laughed. He imagined a chubby L ineffectively chasing after Kira. "L, how fast will you be able to run after you gain 30 kilograms?" He rolled and laughed some more. It was too perfect, he controlled L's body, he could do whatever he wanted and get away with it, he was smart enough to pull it off.

Light rolled around on the bed some more. He imagined L's wrists filling out, his cheeks getting chubbier, and his ass sticking out. "L," he gasped. He felt pleasure building, like when he used the death note, but more intense. Gathering and growing. "L, ah, L." He thought of L, powerless, staring up at him and realizing that Light had done this to him, Light had absolute control over him, and then he would submit to Light and Light would win and he could do whatever he wanted and L might try to fight back at first but he would be powerless and then he would– "Ah!"

Light looked up and was mortified to see Ryuk hovering over him. Not that the Shinigami hadn't seen something like this before, but this was the first time Light had gotten off while thinking of L. ! Light blushed slightly at the implication.

"Light, did you just-"

Light threw a pillow at Ryuk.

"Hyuk, hyuk. You humans really are entertaining."

Light gave the Shinigami a murderous glare. "Shut up, Ryuk."

Then the god of the new world went off to change into a pair of clean underwear.


	2. Chapter 2

**A/N:** Thanks for the reviews and favs! :)

**Disclaimer:** I don't own Death Note

*** Contains Spoilers for the series ***

* * *

L looked down at the waist-line of his jeans. They were almost uncomfortably tight. A normal person would say that they fit perfectly, but L was not a normal person. Gaining weight was not unnerving, but it was slightly inconvenient, as his clothes no longer fit to his liking. He couldn't afford any distractions from the case, not at this point. He needed to spend every second watching Light and Misa on the monitors.

"Watari, it appears that I will be requiring new clothes," L said while scratching one foot against the other.

"Indeed, what size clothes will you require, Master Ryuuzaki?"

L frowned as he detected a hint of sarcasm in Watari's tone.

"Watari, this recent weight gain is suspicious. There is a 67% chance that someone has drugged me, 30% chance it is stress from the case, and 3% chance my body's metabolism is slowing down as I age."

"Perhaps you should eat healthier," Watari suggested. "Incorporating fiber into your diet along with-"

"Body mass is not an accurate indicator of health, Watari." L shifted on his chair. "Now that I think about it the timing is entirely too coincidental for my weight gain to be natural. Whoever is causing this is either involved with the Kira case or trying to get my attention."

If someone had drugged him, then it must be someone on the task force, or closely associated with the task force. Most likely Light or Matsuda. There was a 35% chance it was Light, 40% chance that it was Matsuda (although only 0.00003% chance that Matsuda had done it on purpose), 2% chance it was an outsider, and 8% chance it was another member of the team, most likely Aizawa. And of course, there was another, more insidious possibility.

"You know, Watari, there's a 15% chance it's you. You might be trying to trick me into eating healthier."

"Indeed. Might I remind you that there are easier manners to force children to consume vegetables, if I were inclined to behave in such a fashion?"

L made a face. "Watari, I am almost certain that my recent weight gain is connected to the case. Therefore I will not alter my eating habits, and narrow down my list of suspects based on reactions to my weight gain. Kira is childish and hates to lose. So if he saw me gaining weight, he might gloat. Plus there is a 37% chance that Kira is secretly a chubby chaser."

"…"

"There is nothing to worry about, Watari. I have the situation under control."

"Very well. I shall order several new pairs of clothes for you."

"Thank you, Watari."

x

The next day L started testing his hypothesis. He had Watari order ten flats of strawberries, five packages of marshmallows, twenty-five assorted specialty cakes, some shish-kabob skewers and a mini grill.

He dangled the strawberry in front of his mouth licking it seductively with his tongue. L skewered the strawberry, followed it with a marshmallow, then a piece of cake, put the monstrosity on the grill and covered it in honey. When the honey started to caramelize, L pulled the skewer off the grill and started chewing carefully up one side of the skewer. He moaned loudly in pleasure. Matsuda mumbled an incoherent apology, blushed and ran out of the room. L smiled to himself and gently nibbled on a caramelized strawberry.

Aizawa glared. "Ryuuzaki! Shouldn't you be concentrating on the case?"

"I need sugar to focus," L blandly informed him, popped the entire skewer into his mouth, then pulled it out suggestively.

"Then eat your damn sweets already!" Aizawa fumed. "Why do you have to make such a spectacle of yourself?"

"You seen to be rather tense today, Aizawa," L noted. "Perhaps you should take a break."

Aizawa grumbled something about high-maintenance detectives and stomped out of the room.

L finished eating his sweet monstrosity and started licking his fingers. The results of his first test had been intriguing. He could now rule out Aizawa as a perpetrator of his weight gain (with a +/- 0.005% margin of error). Matsuda was still a possibility, but L doubted that the man had either the brain power or maliciousness necessary to purposefully drug him. L sucked on an index finger and gazed at the monitor. It would be interesting to try his test out on Light next.

x

L had to wait until Misa Amane and Light got back from the hospital before he could move onto his next round of testing. Muscle atrophy was an inconvenient side effect of keeping suspects tied up for nearly two months. It was depressing; he had hoped to get results from the mock execution. Maybe Light wasn't Kira after all…

At least he could investigate his mysterious weight gain while the Kira case stalled. There was a 79.8% chance that the two cases were connected, which therefore meant that he needed to observe both Light and Misa closely for both cases.

L calculated that there was a 3% chance Misa Amane was somehow responsible for his weight gain. She might only be pretending to be an idiot because it was expected of her. There was also the fact that Misa had exclaimed "Wow, you've gotten really fat, Ryuga!" with a little smirk as soon as she had seen him.

Clearly Misa could not be an idiot all of the time, or she never would have been able to meet with the first Kira without L finding out. Of course, Misa's involvement with the Kira case was so obvious that it was entirely possible the whole thing was contrived to frame Light and Misa. Just thinking about all the infinite possibilities was almost enough to give L a headache.

Still, L mused as he finished a piece of tres leche cake, he could at least try and figure out who was behind his weight gain. And it was an excuse to indulge himself in extravagances like the tres leche cake that had been flown in from Mexico that morning, and the chocolate fountain he had Watari purchase yesterday. Maybe he could give the chocolate fountain to Mello as a gift after he finished using it.

"Damn, I've never had such a pathetic date," Misa complained from the other couch.

"Just pretend I'm not here," L said as he dipped a forkful of red velvet cheesecake into the chocolate fountain. He then started licking his creation delicately with the tip of his tongue while covertly watching Light and Misa's responses. Misa scowled at him in disgust. Light twitched slightly and glanced away.

"Ugh, you're such a disgusting pervert, Ryuuzaki." Misa sniffed and turned away from the chocolate atrocity. "No wonder you're so fat."

"Do you want some?" L asked with a full mouth of melted chocolate and cheesecake.

"Eww, cake, I'd get fat just like you," Misa complained. "Besides you probably already have your disgusting perverted germs all over it."

"Your stomach has a pH of approximately two," L informed her. "The acid would kill most micro-organisms that might be in your food."

"Like I'd believe you! You're probably just trying to get me infected with your perverted germs!"

"Ryuuzaki, shouldn't you be working on the case?" Light asked.

"No, I've decided to spend today eating cake instead." L waved a forkful in Light's direction. "Do you want some? It's very good."

"You haven't discovered anything new about the case in over a week," Light pointed out. "What's wrong with you?"

"I suppose I am depressed about the case. And my recent weight gain of course." L smiled surreptitiously. He certainly was not above being emotionally manipulative to get his way. "It's very disconcerting." L mournfully shoveled another forkful of cheesecake into his mouth for added dramatic effect.

"Misa knows why you're gaining weight, Ryuuzaki! You need to eat healthier." Misa leaned back into the couch with a satisfied smirk. "Huh. And I thought you were supposed to be a genius."

A guilty look passed across Light's face before he glanced away again.

_Ha! I'm almost certain you are responsible for my weight gain, Light Yagami,_ L thought_. Now the question is, why and how did you do it?_

x

Light could remember doing a lot of things, but not why he did them. He looked at L, knew he was responsible for his increased weight. It didn't make sense now that he'd try to slow L down, to get him to lose confidence in the case, but it must have made sense back then. It had to have just been a prank then, a harmless prank, or mostly harmless. Maybe Light had been trying to win, to solve the Kira case first. L probably deserved it, after everything he had put Light through.

L was typing on his laptop computer now, still balanced in that ridiculous crouch on the edge of the bed since he couldn't get any farther away thanks to the chain. His chubby cheeks puffed out like a chipmunk under all that fluffy black hair. L could almost be called adorable, if it was ever possible to consider someone like L adorable. His waist was more filed out, and if he lifted his shirt while scratching, Light could see three or four rolls. Neat rolls, tight and symmetrical, not old and stretched out. Light was lying on the bed trying to sleep, but it was kind of hard to sleep with an insomniac detective pounding away on his keyboard.

Light blushed as he thought about his previous response to L's weight gain. He wasn't entirely sure why he had done that either. A part of his brain whispered that it had felt good. Light frowned and pushed the thought away. Now he was tired and just wanted to sleep. "L, if you stay up so late you're going to gain even more weight." Light hadn't mentioned the weight gain before.

Then L closed his laptop with a snap and crawled over. Light grunted as L sat on his chest. L stared down at him. "Light-kun is interested in my weight gain. I wonder why."

"I just want to go to sleep," Light grumbled.

"Why can't you sleep, I wonder?" L brought a finger up to his lip. "Is Kira-kun suffering from a guilty conscience?"

"What? Of course not!" Light tried to push L off but the detective was too damn heavy. "I just can't sleep with you clacking away on the computer."

L leaned forward so that his hair tickled against Light's nose. "Perhaps my weight gain and Yagami-kun's guilty conscience are connected," he said. "I have a hypothesis. Would you like to hear it?"

"No, but I'm sure you'll tell me anyway," Light grumbled, and shifted uncomfortably under L's weight. To his horror he felt himself getting hard.

L leaned forward even more and Light could feel the detective's warm breath against his ear. "You drugged me, Yagami-kun."

"How could that possibly be true? I was confined during most of the time you gained weight."

L's eyes glittered. "You don't directly deny it? Interesting. And you noticed my weight gain started before you were confined."

"That doesn't prove anything."

"I have a second hypothesis, Light-kun, would you like to hear it?"

"No! I'd like to go to sleep instead of listening to you and all your crack-pot hypotheses!"

"I think that Light-kun put the drug in my coffee grounds since I know that he helped Matsuda with the coffee one day. If Light-kun refuses to drink the pre-sweetened coffee, then he is responsible for my weight gain."

Light wrinkled his nose. There was no way he would drink that coffee. And of course L had to frame every test so that if Light behaved like a normal person his Kira percentage would go up, but if he passed the test, his Kira percentage would go up for trying to hard to not act like Kira. "Ryuuzaki, that's unreasonable! You know I hate sweets."

Apparently that was all the proof L needed. "Why did you do it? Were you trying to interfere with the case? If so, your percentage of being Kira-"

"Why does everything have to be about the case?"

L sat back, too far back. He looked surprised for a few seconds, then smirked down at Light. "Or maybe you had a different reason."

x

It was too much, being confined for fifty days, handcuffed to L's wrist, and now the detective was acting like Light could be a mass murderer just because of a stupid, yet ingeniously planned, prank, and L was grinning down at him victoriously, and it wasn't fair. He felt something moving across his stomach as L pressed back and realized L was starting to get hard too.

"Are you ready to admit to your crimes, Yagami-kun?" L taunted.

That was it. Light couldn't take anymore. He punched L and rolled them over so that their positions were reversed.

He didn't know why, but he had a burning urge to get L back for everything he had done, to exert power over him for once. To let the detective know he wasn't as invulnerable as he thought he was. Light leaned forward until his lips were against L's ear, mindful of the bugs and cameras that probably filled the room. "Yes, I did that to you L," Light whispered. "I made you gain weight."

L's eyes widened. "You admit to it?"

Light laughed. It was so satisfying to gloat and sit on top of L and hold his wrists down. It was intoxicating, to have all that power over L, better than he had ever imagined. "Only to you," he whispered, teasing. "You have no proof."

L looked annoyed. He freed one of his hands and grabbed a fistful of Light's shirt. "I'll get proof soon enough."

Light struggled to re-pin L. "Why don't you try having the coffee grounds tested, L?" he teased. "You won't find anything suspicious."

"Maybe I will," L said defiantly.

Light laughed again. "I doubt it," He said confidently. he stared down at L. "How does it make you feel, to be so powerless?"

L somehow twisted his leg up and kneed Light in the stomach. Light rolled over, and L immediately started grabbing at his wrists.

Light kicked L off the bed, and smirked evilly when he heard the portly detective hit the floor with a thud. Too late, he realized that was a really bad idea when he felt L yank on the chain, landed on top of L, and had the wind knocked out of him. L didn't waste any time and tried to wrestle Light to the floor. Light fought back, but he was at a disadvantage with less body mass to use as leverage. As he wiggled out of a headlock, Light discovered a way to use L's bulk against him.

It was extremely satisfying to hold L's soft pliant flesh between his fingers and pinch and twist. Light laughed as L gasped in pain.

L dug his fingers into Light's buttocks and pinched him back. Hard

Light grabbed a fistful of L's fluffy hair in retaliation. He screamed in outrage as L copied his move by grabbing a fistful of Light's up to then perfectly styled hair.

They kept rolling and fighting until they finished, gasping for breath. Light felt a warm sticky liquid fill his underpants.

Light lay on top of L, panting. How was he going to explain this away? Hopefully L had the same problem, but if he did that would mean- !

"Yagami-kun," L said, not meeting his gaze. "Perhaps now would be a good time to clean up and change before bed."

Light stood up. "Fine, I'll go first." He held up the chain expectantly.

L looked at him coyly. "Surely Yagami-kun knows by now that I can't unlock the chain until the Kira investigation is over."


	3. Chapter 3

**Disclaimer:** I don't own Death Note or make any money from this fanfic.

**A/N:** Sorry about the wait. I had to re-structure later chapters in this story, but hopefully it will be finished soon. :/

* * *

Light quickly gathered a clean change of underwear and pajama pants, turned and walked into the bathroom with a huff, L trailing close behind. Once inside, he removed the soiled underpants and started running some water in the sink.

"Do you need any help, Yagami-kun?" L asked.

Startled, Light yelped and turned, and saw L was perched on the edge of the bathtub in his ridiculous crouch. "Ryuuzaki, what are you doing?"

"We're not going to take a bath together?" L asked, and Light could have sworn he heard a note of disappointment in L's voice.

Light gritted his teeth. As much as he hated to pass up an opportunity to shower, the last thing in the world he wanted to do right now was shower with L in an enclosed area while handcuffed. "No. I was just going to change and clean up a little," Light explained. "You should probably do the same."

L gave him one of those cute innocent smiles that he used so often, and brought a finger to his bottom lip, as if Light had said something impressive.

Light turned away, found a washcloth and began cleaning himself off. He hoped that L wouldn't play Mr. Socially Clueless all night in the bathroom. Light was starting to wonder if L pretended to be more clueless than he really was just to annoy him.

He felt hot breath exhale on his ear. "Are you finished yet, Light?"

Light jumped and saw that L had indeed removed his dirty underpants and was now leaning inappropriately close to Light. "Get your own washcloth," Light said as he finished. Light moved away from the sink, picked up a towel and started drying himself off. He watched L fumble with the knobs on the sink and pick up the washcloth with two fingers. L's ass was pretty good looking; it had filled out from all that weight he gained.

L gave him a calculating look, and Light realized he had been staring. "What are you looking at, Yagami-kun?"

Light blushed and quickly pulled on his clean clothes. "Nothing! Just hurry up and stop taking so long!"

L gave him a sly grin, and slowly started wiping himself off.

x

* * *

L crouched in his chair, in the investigation room, and contemplated the most recent developments in the case. Light was industriously working on the Kira case at one of the computers, and occasionally paused to give L a glare. L simply smiled back at him and picked up another plateful of strawberry-topped cake.

Finally Light turned. "Ryuuzaki, are you going to work on the case, or just sit there all day?"

"I am working on the case, Yagami-kun," L said around a mouthful of cake. "I'm simply running calculations in my brain."

Light snorted and went back to his internet research.

L was now stuck with a conundrum. Although Light had confessed to drugging him, he still had no proof. Oh, but he would find proof soon enough, of that he was certain. It was only a matter of time. He could try making Light confess again, this time with more cameras. Or maybe he could find the source of Light's mysterious substance. L had already sent the coffee grounds to a lab for preliminary testing, and they had come back clean, which only served to make L more intrigued, and send them to a more expensive lab for more extensive testing. But the problem was, once he proved without a doubt that Light had drugged his coffee (and there was a 97% chance that Light was the culprit and a 3% chance he had confessed just to mess with L), the only charge he could bring against Light would be – tampering with a food source. And he was sure most of the task force would dismiss Light's actions as a harmless prank.

But L had a bigger problem: Light was guilty of tampering with food, and had shown signs of guilt, and then readily confessed, and those actions did not fit with Kira's profile. Granted, the stakes were not as high in this case, but L had no doubt that Kira would not be so rash as to openly incriminate himself. Even worse was the potential reasoning behind Light's actions. If Light was turned on by L and the thought of him gaining weight, that could explain many of the previous behaviors that had marked Light as Kira. Maybe Light had been so secretive in his room because he was hiding a second stash of porn that he didn't want anyone to know about. Maybe he had allowed himself to be confined merely to get closer to L.

L gnawed on his fork and scraped the last bits of icing off his plate. No, he couldn't dismiss Light as a suspect so easily. First of all, there was the fact that Light had gloated during his confession, which fit with Kira's profile. Secondly, it was possible that Light had faked the entire incident merely to mess up L's profile. If that was the case…then there was a 60% chance that Light was faking his attraction to L. Which meant of course, that L needed to seduce him in order to find out whether or not he was faking. Purely for the case. And Kira was very clever, so L probably needed to seduce him more than once.

L got another piece of cake and moved his chair closer to Light's. Naturally, the entire situation was far more complicated than Light faking or not faking his attraction. He could still be Kira, even if he had drugged L for sexual reasons. L smiled. Either way, it was a weakness to exploit.

x

* * *

Light paused and stretched as he continued to search Kira's recent killings for any trace of a pattern.

"Light-kun, I require assistance."

Light's eye twitched as he turned to face L, who had moved his chair right next to Light's. "What do you need?" Light asked, suspicious of L's motives.

"I need to perform an experiment," L said, scratching one toe against his leg. "and for that I need Light-kun to feed me."

Light turned away in disgust. "Ask Watari to do that for you."

"You misunderstand, Light-kun." L gave him another Mr. Socially Clueless look. "I simply want to find out if being fed instead of feeding myself increases brain function."

"I don't understand why Watari can't do that-"

"Watari is busy at the moment."

Light gave L an indignant look. "And I'm not?"

L brought a finger to his lip. "No, at the moment you are currently arguing with me instead of working on the case."

Before Light could protest further, the plate was shoved into his hands, and L was gazing at him with a look that was almost sultry, if such a thing was possible. Light sighed and picked up the fork deciding that going along with L's crazy request was less of a headache than arguing. And honestly, it wasn't entirely unappealing.

L reached out and grabbed the fork from Light's hands. "Use your fingers, Yagami-kun." Then he shoved a hand wipe at him. "Make sure you disinfect them first." L paused and gave Light a clean towel. "And wipe off the disinfectant. It tastes terrible."

Light glared, but stuck his fingers into the soft sticky cake and pulled off a chunk, then he held it up to L's face.

L daintily picked up the cake in his teeth and quickly swallowed. Then he licked off all traces of frosting from Light's fingers, his tongue sensually flicking out.

Light pulled his hand back and picked up a strawberry covering in white icing. L eagerly licked at the icing and nibbled at the strawberry, the red juice dribbling down his chin. Occasionally his tongue would flick against Light's fingers.

Light suppressed a groan. Damn, it was so hot to see L like this, eating out of his hands, giving him heated looks, and tilting his head back and moaning with pleasure at every influx of sugar. L licked his hand again, and Light felt pressure building in his groin. Thanks to the stupid handcuffs he wouldn't be able to get any release, at least not for a while. Light groaned again as he imagined having to concentrate on his internet search with a raging hard-on, and with L sitting right there next to him. It was torture! It had to be. Light narrowed his eyes and watched L's display.

L finally finished his cake. "Thank you for your assistance, Yagami-kun," was all he said.

Light wiped his hand off and turned back to the computer. He shifted so his erection wasn't visible (he hoped!) and tried to concentrate on the case.

"Is there a problem, Yagami-kun?" L asked, with a smile that nearly resembled a smirk.

"No," Light replied, and stubbornly starting typing.

L leaned closer and placed a hand on Light's shoulder. He was close enough that his breath moved Light's hair and tickled against his neck. "Are you sure?"

Light shifted again in his chair. It was so uncomfortable to be hard and not be able to do anything about it, and L wasn't helping with his closeness. Light decided he couldn't take it anymore. "L," he said through gritted teeth, "I need to use the restroom. By myself."

"Surely Yagami-kun knows I can't allow that," L said.

Light turned and glared at L.

L glanced down at the noticeable bulge in Light's pants. "Are you going to need help with that, Light-kun?"

"Fuck you," Light muttered under his breath.

"No, actually I think a hand-job might suffice for now." L brought a finger to his lip. "That is, unless Light wishes to continue working while in such a state. And with that volume of blood in his genitals instead of his brain, I imagine his reasoning skills would decrease by-"

Light groaned. He was trapped. L wouldn't give him any privacy, and he wasn't sure his hard-on would go away with L continuing to sit so close and breathe on him. He could try to work through the day anyway, but L was right, he wouldn't be able to pay much attention, and then the detective might accuse Light of trying to sabotage the investigation. Maybe he should just let L give him a hand-job. A part of his brain enthusiastically agreed and pointed out that L's beefy hands would feel quite good. It had felt good last night, why not again right now? Just as long as it was clear he was the dominant one.

"Fine," Light said, glancing around. "But we can't do it here."

L gave him a little smile.

x

* * *

Light was surprised when L ran towards the bedroom, dragging him behind with the chain. L sat down on the bed and leaned back seductively.

Light inhaled, and L smirked at him, challenging.

He realized that this was a game too, just like the tennis match, except that Light didn't know all the rules yet. It wasn't fair, but since when had L ever played fair? It was just like tennis though; if he wanted to win this game he'd have to attack, without hesitation.

Light leaned forward, and pressed his lips to L's. It wasn't as revolting as he imagined it would be, in fact it felt quit nice. L inhaled sharply, and Light pulled back. Yes he needed to surprise L, pull an unexpected move to put the detective off-balance.

"Ryuuzaki," he said, and grabbed a fistful of black fluffy hair. But he was gentle this time as he tilted L's head back and kissed his neck. He did a mental victory dance as he heard L's surprised gasp. Yes, he would have to get creative to keep ahead of L.

Then it was his turn to gasp as he felt L's long spindly fingers grabbing at the hem of his shirt and traveling underneath, ghosting along his skin, then pressing harder.

Light stopped kissing L's neck and leaned away, indignant. "Ow, hey, that-"

"Is Yagami-kun ticklish?" L asked with an evil glint in his eye.

"What? No , of course not," Light said, inching away from L.

Then L moved like an alligator, quicker than Light thought was possible considering his size and temperament, knocked Light down onto the bed and climbed over and sat heavily on his stomach.

"Cheater," Light hissed when he was able to partially regain his breath.

"But this is the most efficient way to take care of Kira-kun's problem," L said innocently, tilting his head. "Unless you are trying to sabotage the case." He shifted and started fumbling with the zipper on Light's trousers.

Light glared back, but then decided maybe this wasn't so bad after all as he felt L reaching into his underpants. Yes, next time he would win for sure, but he wasn't exactly losing if he was the one making L do this to him, was he?

He shifted on the bed and helped L pull his pants and underwear down the rest of the way. L reached back and grabbed hold of his already hard length, and then started to inspect it as if it were a particularly unusual specimen.

"That looks painful, Yagami-kun," L observed.

Light gritted his teeth. "I thought you wanted to get this done as soon as possible."

"Hmm, yes of course," L said and started stroking.

L's hands felt amazing and soft and chubby around him and Light knew he wouldn't last long. Light clutched the bed sheets and panted. "Ryuuzaki," he gasped out, "I'm going to-"

"L!" Light screamed as a wave of pleasure washed over him.

Damn, that had been…better than thinking about L. Maybe. Light rolled over on his stomach and rested.

L shifted awkwardly on the bed and pulled on the chain. "Can we get back to work now, Light-kun?"

Light groaned and shakily got up. There were definite disadvantages to getting off with a co-worker. Especially a work-aholic insomniac co-worker like L.


End file.
